I have the same problem.
As Aurélien Gâteau, I was able to make it run by entering the key in hexadecimal rather than in ascii. (see https://bugs.launchpad.net/ubuntu/+source/plasma-widget-network-manager/+bug/339313/comments/7)
In Ubuntu (Gnome) works without problems
I have the same problem.
As Aurélien Gâteau, I was able to make it run by entering the key in hexadecimal rather than in ascii. (see https:/ /bugs.launchpad .net/ubuntu/ +source/ plasma- widget- network- manager/ +bug/339313/ comments/ 7)
In Ubuntu (Gnome) works without problems